Make ld-android.so export linker symbols

ld-android.so exports exact same set of symbols
as linker. Since it is not supposed to be loaded
every symbol points to fail() method.

Test: make
Test: bionic-unit-tests --gtest_filter=dl*
Change-Id: I23bec365b302ce4ddf5f08832e665ae2b181cf8a
diff --git a/linker/ld_android.cpp b/linker/ld_android.cpp
new file mode 100644
index 0000000..8e8608b
--- /dev/null
+++ b/linker/ld_android.cpp
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <stdlib.h>
+#include <sys/cdefs.h>
+
+extern "C" void __somehow_you_managed_to_not_get_the_actual_symbols_from_the_linker();
+
+extern "C" void __ld_android_init() __attribute__((constructor));
+
+void __ld_android_init() {
+  __somehow_you_managed_to_not_get_the_actual_symbols_from_the_linker();
+}
+
+extern "C" void __internal_linker_error() {
+  abort();
+}
+
+__strong_alias(__loader_android_create_namespace, __internal_linker_error);
+__strong_alias(__loader_android_dlopen_ext, __internal_linker_error);
+__strong_alias(__loader_android_dlwarning, __internal_linker_error);
+__strong_alias(__loader_android_get_application_target_sdk_version, __internal_linker_error);
+__strong_alias(__loader_android_get_LD_LIBRARY_PATH, __internal_linker_error);
+__strong_alias(__loader_android_get_exported_namespace, __internal_linker_error);
+__strong_alias(__loader_android_init_anonymous_namespace, __internal_linker_error);
+__strong_alias(__loader_android_link_namespaces, __internal_linker_error);
+__strong_alias(__loader_android_set_application_target_sdk_version, __internal_linker_error);
+__strong_alias(__loader_android_update_LD_LIBRARY_PATH, __internal_linker_error);
+__strong_alias(__loader_cfi_fail, __internal_linker_error);
+__strong_alias(__loader_dl_iterate_phdr, __internal_linker_error);
+__strong_alias(__loader_dladdr, __internal_linker_error);
+__strong_alias(__loader_dlclose, __internal_linker_error);
+__strong_alias(__loader_dlerror, __internal_linker_error);
+__strong_alias(__loader_dlopen, __internal_linker_error);
+__strong_alias(__loader_dlsym, __internal_linker_error);
+__strong_alias(__loader_dlvsym, __internal_linker_error);
+#if defined(__arm__)
+__strong_alias(__loader_dl_unwind_find_exidx, __internal_linker_error);
+#endif
+__strong_alias(rtld_db_dlactivity, __internal_linker_error);
+